Traction Means Tensioner, Vibration Welding Device Having a Traction Means Tensioner as well as Production Method for a Traction Means Tensioner

ABSTRACT

With the traction mechanism tensioner, a traction mechanism having at least two ends is tensionable. The traction mechanism tensioner comprises a first fastener, a second fastener and a coupler. The first fastener has a first fastening portion at which the first end of the traction mechanism as fastenable. The second fastener has a second fastening portion at which the second end of the traction mechanism is fastenable. The coupling means couples the first and the second fasteners to each other so that the first and the second fasteners are movable with respect to each other and their movability is at least restricted on one side. Further, the first and the second fasteners are pre-tensionable with respect to each other via at least one spring element.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.14/471,155 filed Aug. 28, 2014 which claims the priority of Germanpatent application DE 102013217272.9, filed on Aug. 29, 2013. The entirecontent of this priority application is incorporated herein byreference.

TECHNICAL FIELD

The present disclosure is related to a traction means/mechanismtensioner, the usage of a traction means tensioner in a welding device,a vibration welding device having a traction means tensioner, aproduction method for a traction means tensioner, a retrofitting methodfor a welding device as well as a tensioning method for a tractionmeans.

BACKGROUND

Electrically driven vibration welding devices have been capturing themarket increasingly in the past years. A vibration welding system of thevibration welding device, especially an oscillating head, is commonlydriven electrically. In contrast thereto, advancing systems of thevibration welding device were operated for a long time hydraulically orrarely pneumatically. The term advancing system comprises herein allmovable elements of the vibration welding device which cause that afirst work piece to be welded is moved towards or threaded into a secondwork piece to be welded, which is arranged at the oscillating head. Forexample, a lifting table as element of the advancing system of thevibration welding device has been driven hydraulically for years. Theusage of electrical drives, as for example a spindle drive, was criticalto impossible due to the vibrations or oscillations of the vibrationwelding device. This is especially founded in that both of the workpieces to be welded have to be pressed against each other during thewelding process itself and thus a vibration is transferred to allelements of the vibration welding device, also to the spindle drivepressing both work pieces to be welded against each other. However, thespindle drive is not designed or suited for such vibration loads so thatthe durability of the spindle drive is shortened respectively.

Therefore, an electrical drive for the advancing system was developedyears ago by the company BRANSON, which uses a traction means, namelychains or belts. An element of the advancing system to be moved, forexample the lifting table, is herein coupled to the traction meansfirmly. The traction means itself is moved by an appropriate drive, forexample by a servomotor or an asynchronous motor. In contrast to thespindle drive, the traction means are able to absorb the oscillationsproduced by the oscillating head of the vibration welding device and tooscillate therewith, if necessary. As the oscillations produced by theoscillating head are transferred inevitably also to a machine frame andto the lifting table of the vibration welding device, a co-vibration ofthe traction means is even more important.

Especially with respect to the welding process of a vibration weldingdevice, a force is applied to the work pieces to be welded in that theadvancing system, especially the lifting table, presses the first workpiece to be welded against the second work piece to be welded, which isarranged at the oscillating head. In doing so, the traction means, thusthe belt or the chain, is tensioned strongly in the area of the workpieces to be welded while the tension of the traction means is releasedon the side opposite to the work pieces to be welded.

A general disadvantage resulting from using traction means, especiallyin vibration welding devices, is that the traction means is elongatedwith time. Such an elongation has to be compensated usually manually toavoid malfunction or increased wear.

Particularly with respect to belts, especially toothed belts, astraction means, they have to be re-tensioned in a shorter operating timecompared to chains as traction means. Also, the failure source at beltsexists that the tension is adjusted too high or too low. Furthermore,and based on experience, the belts rapidly lose tension especially atthe beginning, thus at their first use, and have to be re-tensionedquickly.

In case it is reacted to this initially large elongation with arespectively higher pre-tension, this results in a hard running of thedevice. Accordingly, a disproportional amount of energy is required formoving the advancing system. Furthermore, the wear in the used bearingsis increased, which results in turn in a shortened durability of theadvancing systems.

Similar problems exist when chains are used. They don't have to bere-tensioned after such a short operating time compared to belts butchains are also elongated over time due to wear.

Furthermore, and due to the releasing of the traction means on one side,there is the disadvantage that a driving by for example a drive geardoes not take place reliably any longer. Further, it is also possiblethat the traction means jumps out of a guide and thus a proper operationof the vibration welding device is no longer ensured. For avoiding this,a manual readjustment of the traction means is being done for now.

It is thus the object of the present innovations to provide a tractionmeans tensioner by means of which an automatic re-adjustment of thetension of the traction means, especially at the usage in weldingdevices like vibration welding devices, is possible. Furthermore, acorresponding production method for a respective traction meanstensioner shall be given.

SUMMARY

One or more objective technical problems are solved by a traction meanstensioner according to patent claim 1, the usage of a traction meanstensioner according to patent claim 9, a welding device according topatent claim 11, a production method of a traction means tensioneraccording to patent claim 13, a retrofitting method of a welding deviceaccording to patent claim 14 as well as a tensioning method for atraction means according to patent claim 16. Further preferredembodiments result from the following description, the drawings as wellas the dependent patent claims.

The traction means tensioner, by means of which a traction means istensionable, which has at least a first and a second end, preferablyonly two ends, comprises a first fastening means having a firstfastening portion at which the first end of the traction means isfastenable, a second fastening means having a second fastening portionat which the second end of the traction means is fastenable, and acoupling means coupling the first and the second fastening means to eachother so that the first and the second fastening means are movable withrespect to each other and their movability is at least restricted on oneside, wherein the first and the second fastening means arepre-tensionable via at least one spring element with respect to eachother.

For a better understanding of the traction means tensioner, the tractionmeans tensioner is described in the following during usage in avibration welding device. Here, the application of the traction meanstensioner is not limited to the usage in a vibration welding device butmay also be used generally in welding devices as well as in all devicesin which a reciprocating movement of a movable component of the deviceshall be caused by means of a traction means.

The exemplary vibration welding device comprises a lifting table atwhich the traction means tensioner is arranged. Further, the vibrationwelding device comprises an oscillating head, arranged at an upper endof a machine frame. The first end of the traction means is connected tothe first fastening portion of the first fastening means and the secondend of the traction means is connected to the second fastening portionof the second fastening means. The traction means runs from the firstfastening portion of the first fastening means in the direction of theupper end of the machine frame, at which the traction means isdeflected, preferably at a deflection pulley. From there, it runs in thedirection of the lower end of the machine frame to a driving gear whichis coupled to a motor via a shaft. From the driving gear, the tractionmeans runs again in the direction of the upper end of the machine frameto the second fastening portion of the second fastening means. As thefirst and the second fastening means are coupled directly or indirectlyto each other via the coupling means, the two ends of the traction meansare also coupled to each other in this manner by means of an in-linearrangement of the traction means tensioner. The traction means isdrivable by means of the driving gear, which is driven via the motor, sothat the lifting table is movable preferably in the vertical direction.

In this embodiment, the traction means tensioner is used with a tractionmeans, which enables a vertical reciprocation. Here, it has to beconsidered that the traction means tensioner cannot only be used with atraction means allowing a vertical reciprocation but with each tractionmeans realizing a reciprocation of a component to be moved, regardlessof the direction.

For adjusting an appropriate tension of the traction means beforeoperating the vibration welding device, the first and the secondfastening means are connected directly or indirectly to each other viathe coupling means so that the first and the second fastening means aremovable relatively to each other. In a first embodiment, only one of thetwo fastening means is movable while the other is stationary withrespect to the coupling means. In an alternative embodiment, bothfastening means are movable with respect to the coupling means. In eachcase, the movement of the at least one fastening means is preferablylimited so that the coupling means restricts the deflection of one endof the traction means at least in one direction.

The desired or pre-determinable tension of the traction means isproduced by means of the at least one spring element. The at least onespring element is chosen from the group consisting of: helical springs,spiral springs, flat springs and disc springs or a combination thereof.Therein, the at least one spring element fulfils also the object ofmaintaining the predetermined tension during an operation of thevibration welding device. In case an elongation of the traction meansoccurs during the operation, the at least one spring element thenchanges the position of the first and the second fastening means andthus of the first and the second end of the traction means with respectto each other so that the desired tension at the traction means is inturn re-adjusted or maintained. This means that the at least one springelement is pre-tensioned against a traction direction of the tractionmeans. By means of the at least one spring element, also a first forcein a first direction is applied to one of the fastening means, whereinsaid first force acts oppositely to a second force, wherein said secondforce is applied by the corresponding end of the tractions means to therespective fastening means in a second direction being opposite to thefirst direction. For example, the at least one spring element may beassigned to the second fastening means. The traction element applies aforce to the second fastening means via the second fastening portionpulling the second fastening means away from the coupling means. The atleast one spring element acts against this force and pulls the secondfastening means towards the coupling means or towards the firstfastening means, whereby the traction means maintains the desiredtension during operation and the two fastening means are pre-tensionedwith respect to each other.

An advantage of the preferred traction means tensioner is thus that thetraction means may be tensioned flexibly. Further, the traction meanstensioner may be constructed variably. It may also be used with aplurality of different traction means types and sizes so that it isextremely economical. Furthermore, the preferred traction meanstensioner has a compact design and is especially not much wider than thetraction means itself.

According to a preferred embodiment, the at least one spring element isarranged adjacent to the second fastening means and the second fasteningmeans comprises a securing portion arranged in the coupling means.Alternatively, the at least one spring element may also be assigned tothe first fastening means. In each of these embodiments it is importantthat by means of the assignment or adjacent arrangement of the at leastone spring element to one of the fastening means, the respectivefastening means is movable with respect to the coupling means. In thefirst preferred case, the second fastening means is thus movable withrespect to the coupling means.

Further, and in case of failure of the at least one spring element, therespective fastening means does not slide out of the coupling means dueto a traction of the traction means. This is achieved by the arrangementof the securing portion of the fastening means in the coupling means,which is arranged adjacent to the at least one spring element. In thefirst preferred case, this is also the second fastening means. Thesecuring portion ensures a positive fit coupling of the respectivefastening means with the coupling means. Especially in case of a failureof the spring element, the securing portion having the positive fitcoupling to the coupling means ensures that the corresponding fasteningmeans is not able to be released from the coupling means in tractiondirection of the traction means. Accordingly, and in such a case, therespective end of the traction means is further coupled to the couplingmeans. Thus, and for example, the vibration welding device is at leastmovable in emergency service into a position, in which a replacement ofthe at least one spring element is possible without problems.

Additionally or alternatively, a monitoring of the spring element or thefastening means arranged adjacent thereto via sensors is possible. Indoing so, an operation of the traction means tensioner in a load limitrange is recognisable timely so that appropriate measures like astopping of the exemplarily vibration welding device and/or areplacement of the spring element by a spring element having the same orother characteristics may be taken.

In an especially preferred embodiment, particularly with respect to theabove described embodiment, the first fastening means is stationary withrespect to the coupling means. This applies especially in case the atleast one spring element is arranged adjacent to the second fasteningmeans. In case the at least one spring element is arranged adjacent tothe first fastening means, the second fastening means is arrangedstationary with respect to the coupling means. By means of thisarrangement of a movable and a stationary fastening means with respectto the coupling means, a tension of the traction means may be adjustedespecially efficient.

It is also preferred that the coupling means couples the first and thesecond fastening means to each other so that the first fastening portionof the first fastening means and the second fastening portion of thesecond fastening means are oriented in opposite axial directions. Inthis way, especially a continuous traction means can be replaced by atraction means having two ends without changing the remainingconstruction of the exemplary vibration welding device extensively. Thisapplies correspondingly to all devices wherein the traction means isused for reciprocating an element or component.

Further, it is preferred that the coupling means comprises a regulatingor adjusting portion, especially a thread, so that an initial distancebetween the first and the second fastening portion is pre-determinable.By means of this regulating portion, an initial position of the twofastening means with respect to each other is adjustable beforefastening a respective end of the traction means to the first and thesecond fastening portion. This applies especially to an initial distancebetween the two fastening portions in case the two fastening portionsare oriented by the coupling means in opposite axial directions. Asdescribed above, and during operation of the exemplary vibration weldingdevice, an automatic re-adjustment of the desired or a predeterminedtension occurs due to the at least one spring element in case of anelongation of the traction means. For further increasing the easyhandling of the device, a means is provided with this embodiment bymeans of which the pretension of the traction means is additionally alsomanually re-arrangeable or re-adjustable. Thus, it is possible withoutgreat effort and besides the automatic re-adjustment of the tension ofthe traction means to perform a manual adjustment of the pretensionwithout changing the components.

In a further preferred embodiment, the at least one spring element is ahelical spring arranged with a first axial end at the second fasteningmeans, especially at the second fastening portion, and with a secondaxial end at the coupling means so that the first and the secondfastening means are pre-tensionable with respect to each other. By meansof the helical spring, the desired pretension of the traction means ispredetermined, for example by means of a respective choice of thematerial for the helical spring, the thread pitch or othercharacteristics. A special advantage is present in case the helicalspring is arranged accessible from the outside at the coupling means aswell as at the second fastening means. In case of a failure of thehelical spring, it is replaceable any time easily. Preferably, at leasttwo spiral springs are used.

In an alternative embodiment, the at least one spring element is a discspring arranged around the second fastening element between a securingportion of the second fastening element and an opening in the couplingmeans so that the first and the second fastening means arepre-tensionable with respect to each other. This arrangement is, inprinciple, similar to a piston-cylinder-arrangement like in shockabsorbers, wherein the second fastening means represents the piston andthe coupling means represents the cylinder. The securing portion of thesecond fastening means is arranged in the coupling means and the secondfastening means protrudes through the coupling means via an opening sothat at least the fastening portion of the second fastening means isfreely accessible. The disc spring is arranged between the securingportion and the opening of the coupling means through which the secondfastening means protrudes. In this embodiment, it is especiallyadvantageous that the disc spring is arranged protected and that aparticular compactness of the traction means tensioner results.Preferably, an even plurality of disc springs is used, which arearranged alternatingly with the upper and lower side to each other.

The traction means tensioner is used in a welding device, especially ina vibration welding device, an infrared welding device, a hot platewelding device or in combinations thereof. Here, it is especiallyadvantageous to use a chain or a belt as traction means. The respectiveadvantages result from the above description of the traction meanstensioner according to the invention and are thus not repeated here.

The welding device, especially a vibration welding device, comprises amovably arranged element, especially a lifting table, a traction meansfor moving the movably arranged element, especially for a reciprocatingmovement of the lifting table, and a traction means tensioner.Preferably, the traction means tensioner is arranged at the movablyarranged element, thus especially at the lifting table. The advantagesof the welding device as well as its functionality were alreadydescribed above in combination with the traction means tensioner.Therefore, the advantages of such an arrangement are not repeated here.

The production method of a traction means tensioner, especially of atraction means tensioner, comprises the steps of: providing a firstfastening means having a first fastening portion at which a first end ofa traction means is fastenable, providing a second fastening meanshaving a second fastening portion at which a second end of a tractionmeans is fastenable, providing a coupling means and arranging the firstand the second fastening means at the coupling means so that the firstand the second fastening means are movable with respect to each otherand their movability is at least restricted on one side, and arrangingat least one spring element so that the first and the second fasteningmeans are pre-tensionable with respect to each other by means of the atleast one spring element. With respect to the advantages of the tractionmeans tensioner produced in this way, it is referred to the abovedescription of the traction means tensioner.

A retrofitting method for a welding device, especially a vibrationwelding device, comprises the steps of: providing a traction meanstensioner, separating a continuous traction means of the welding device,especially a continuous chain or a continuous belt, so that the tractionmeans has two ends, coupling the first end of the traction means to thefirst fastening portion of the first fastening means of the tractionmeans tensioner, coupling the second end of the traction means to thesecond fastening portion of the second fastening means of the tractionmeans tensioner, and arranging the coupling means of the traction meanstensioner at the welding device, especially at an element of the weldingdevice which is movable by means of the traction means. In a preferredembodiment, the method comprises the further step of: adjusting apretension of the traction means by means of adjusting the distancebetween the first fastening portion of the first fastening means and thesecond fastening portion of the second fastening means, especially bymeans of a regulating portion of the coupling means.

By means of the retrofitting method, any welding device having anelement which is movably arranged by means of a traction means may beprovided with the traction means tensioner. The advantages resultingtherefrom were already described in combination with the traction meanstensioner so that they are not repeated here.

A tensioning method for a traction means having at least a first and asecond end comprises the following steps of: connecting the first andthe second end of the traction means via a coupling means so that thefirst and the second end of the traction means are movable with respectto each other and their movability is at least restricted on one side,arranging at least one spring element so that the first and the secondend of the traction means are pre-tensionable with respect to eachother, and changing a relative distance between the first and the secondend of the traction means, which are connected via the coupling means sothat the traction means is pre-tensioned by means of a spring pretensionbetween the first and the second end.

With the tensioning method, a traction means having at least two endsmay be tensioned effectively, especially when using the traction meanstensioner. With respect to the different advantages, it is thus referredto the above statements for the traction means tensioner according tothe invention to avoid repetitions.

In a preferred embodiment of the tensioning method, the step ofconnecting the first and the second end of the traction means via acoupling means comprises the steps of: coupling the first end of thetraction means to a first fastening means coupled to the coupling means,coupling the second end of the traction means to a second fasteningmeans coupled to the coupling means, wherein the first and the secondfastening means are movable with respect to each other and theirmovability is at least restricted on one side so that a relativedistance between the first and the second end of the traction means isadjustable. Further, it is preferred that the first and/or the secondfastening means are coupled to the coupling means by means of a positivefit so that a protection against a releasing of the first and/or thesecond end of the traction means from the coupling means is formed,especially in a traction direction of the traction means. Also, and withrespect to this preferred embodiment of the tensioning method, it isreferred to the statements for the traction means tensioner according tothe invention.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following, embodiments and implementations of the presentinvention are described in detail with reference to the accompanyingdrawings. Same reference numbers in the drawings denote the same partsor components. It shows:

FIG. 1 shows a vibration welding device according to a first embodimentof a traction means tensioner according to the invention,

FIG. 2 shows a section of the vibration welding device of FIG. 1,

FIG. 3 shows a side view of the vibration welding device of FIG. 2,

FIG. 4 shows the first embodiment of the traction means tensioneraccording to the invention,

FIG. 5 shows a side view of the traction means tensioner of FIG. 4,

FIG. 6 shows a second embodiment of the traction means tensioneraccording to the invention,

FIG. 7 shows a side view of the traction means tensioner according tothe invention of FIG. 6,

FIG. 8 shows a schematic course of the procedure for a production methodaccording to the invention for a traction means tensioner,

FIG. 9 shows a schematic course of the procedure for a retrofittingmethod according to the invention, and

FIG. 10 shows a schematic course of the procedure for a tensioningmethod according to the invention.

DETAILED DESCRIPTION

The traction means (i.e. traction mechanism) tensioner according to atleast some implementations of the invention is described in thefollowing on the basis of the usage in a vibration welding device. Thisusage is, however, not restrictive as the traction means tensioneraccording to the invention may be used in any device or machine in whicha reciprocating movement of a component shall be caused by means of atraction means. Especially, a continuous traction means which solelycauses a reciprocating movement of a component may be replaced by atraction means (i.e. traction mechanism) having two ends combined withthe traction means tensioner according to the invention.

Now, and with reference to FIG. 1, a vibration welding device 1 isdepicted. The vibration welding device 1 comprises a machine frame 10having an oscillating head 12 and a lifting table 14. The lifting table14 is guided in vertical direction by columns 16 and bearing bushings18. During operation of the vibration welding device 1, one work pieceto be welded is arranged on the lifting table 14 and the oscillatinghead 12, respectively. For moving the lifting table 14 in the directionof the oscillating head 12 and for applying a force to the two workpieces to be welded during the welding process itself, a motor 20 havinga gear 22 is provided. The motor drives a shaft 24 via the gear 22,wherein two driving gears 26 are arranged at the shaft 24. Each of thedriving gears 26 is in engagement with a respective traction means 28.The traction means 28 may be a chain or a belt, especially a toothedbelt.

Further, a first embodiment of the traction means tensioner 30 accordingto the invention is recognizable in FIG. 1. Now, and with reference toFIGS. 2 to 5, the traction means (i.e. traction mechanism) 28 isarranged with a first end at the first fastening portion 42 of the firstfastener (e.g. first fastening means) 32. This arrangement takes placeespecially by means of a fastening pin 44. Likewise, the second end ofthe traction means 28 is arranged at the second fastening portion of thesecond fastener (e.g. second fastening means) 34 via a fastening pin 50.In this case, the coupling mechanism or means has a receiving mechanismor means 36, which comprises in the depicted case in turn four screws54, and a retaining mechanism or means 40. On the one side of theretaining means 40, the first fastener 32 is fastened stationary bymeans of the screws 46 and the locknuts 48. At the opposite side of theretaining means 40, the receiving means 36 is fixed. In this manner, aconnection to the lifting table 14 is created via the retaining means40.

A movement of the second fastening means 34 is thus limited by means ofthe retaining means 40 in a first axial direction and by means of asecuring portion 56 of the second fastening means 34 in combination withthe opening in the receiving part 36 in a second axial direction. Thesecuring portion 56 forms thus a positive fit coupling in combinationwith the opening 66 in the receiving part 36. For this purpose, thesecuring portion 56 has a larger lateral extension as a following web 68being adapted in its width to the opening 66 in the receiving means 36.In this manner, the second fastening means 34 is axially movablyarranged and retained at least partly in the receiving means 36.

When using the traction means tensioner 30, the tension of the tractionmeans 28 is predetermined by means of appropriate elastic tensionelements, here the helical springs 38, which are mounted to the secondend of the traction means or the second fastening portion of the secondfastening means 34 and the receiving means 36. To this end, two holders52 for a first axial end of the helical springs 38 are provided at thereceiving means 36. The second axial end of the helical springs 38 isarranged at the fastening pin 50. Even in case of failure of one or bothhelical springs 38, the fastening means 34 is not able to be releasedfrom the receiving means 36, especially not able to slide out or to bepulled out.

Preferably, helical springs are used in this embodiment, whereincertainly also other spring elements are conceivable, which produce atension and a reset force. The spring force of the spring elements hasto be chosen so that on the one hand an appropriate tension is created.On the other hand, the spring element may not be overstressed during thewelding process so that the tension thereof is lost.

An alternative embodiment is shown in FIGS. 6 and 7. Herein, thecoupling means or coupler has an elongated housing 60, in which thereceiving means or receiver 36 is arranged on the one side and the firstfastening means 32 is arranged on the opposite side. FIG. 7 shows arespective sectional view. In the receiving means 36, disc springs 62 asspring elements are arranged between a securing portion 56 of the secondfastening means 34 and an opening 66 of the receiving means 36. Here,too, the securing portion 56 comprises a larger diameter as the opening66, similar to the above described first embodiment. The secondfastening means 34 protrudes through the opening 66 with a portionhaving a smaller diameter, which follows the securing portion 56 andwhich then passes over into the second fastening portion 64. The discsprings 62 are four disc springs 62, which are arranged respectivelyalternatingly with their upper and their lower side to each other.

It can be seen that the receiving means 36 is retained in the housing 60by means of a thread. Via the thread in the housing 60, a relativedistance of the first 42 and the second fastening portion 64 to eachother can be adjusted, whereby, in case the traction means 28 is coupledto the respective fastening portion 42, 64, a pretension for thetraction means 28 is adjustable. For this reason, the portion having thethread is also denominated as regulating or adjusting portion. Aposition of the receiving means 36 in the housing 60 is fixed by meansof a locking nut 58. Thus, a pretension is adjustable. Furthermore, andbesides the automatic tension maintaining due to the disc springs 62, amanual re-adjustment of the pretension of the traction means 28 may beachieved in this manner by releasing the locking nut 58, adjusting thedistance between the two fastening portions 42, 64 via the regulatingportion and tightening the locking nut 58.

The first fastening means 32 may be arranged at least partly in thehousing 60 in a positive fit and/or a non-positive fit manner, as shownin FIGS. 6 and 7. For example, it may be arranged therein loosely, itmay be coupled thereto rigidly or it may be coupled thereto via thethread. Due to the enlargement of the first fastening means 32 at theend axially opposite to the first fastening portion, the first fasteningmeans cannot be pulled out of the housing, especially not by thetraction means.

The tensioning method realised by the traction means tensioner can bedescribed with respect to FIG. 10 as follows. In a first step a, thefirst and the second end of the traction means 28 are coupled via thecoupling means so that the first and the second end of the tractionmeans 28 are movable with respect to each other and at least restrictedon one side. The coupling of step a comprises therein two steps. In stepd, the first end of the traction means 28 is coupled to the firstfastening means 32, and in step e, the second end of the traction means28 is coupled to the second fastening means 34. The first 32 and thesecond fastening means 34 are coupled to the coupling means. In thisway, the first 32 and the second fastening means 34 and thus also thefirst and the second end of the traction means 28 are movable withrespect to each other and at least restricted on one side so that arelative distance between the first and the second end of the tractionmeans 28 is adjustable. The steps d and e may be performed in any order.Preferably, the first 32 and/or the second fastening means 34 arecoupled to the coupling means with a positive fit so that a protectionagainst a releasing of the first and/or the second end of the tractionmeans 28 from the coupling means is formed, especially in a tractiondirection of the traction means 28.

In step B, the arrangement of at least one spring element 38; 62 followsso that the first and the second end of the traction means 28 arepre-tensionable with respect to each other. Finally, in step c thechanging of a relative distance between the first and the second end ofthe traction means 28 follows, which are coupled via the coupling means,so that the traction means 28 is pre-tensioned via a spring pretensionbetween the first and the second end.

The production method according to the invention for a traction meanstensioner is now described with reference to FIG. 8. In a step A, thefirst fastening means is provided having the first fastening portion atwhich the first end of the traction means is fastenable. In step B, thesecond fastening means is provided having a second fastening portion atwhich the second end of the traction means is fastenable. In step C, acoupling means is provided. The steps A to C may be performed in anyorder.

Arranging the first and the second fastening means at the coupling meansis performed in step D so that the first and the second fastening meansare movable with respect to each other and at least restricted on oneside. Further, and in step E, arranging of the at least one springelement is performed so that the first and the second fastening meansare pre-tensionable with respect to each other via the at least onespring element. In this way, the traction means tensioner according tothe invention is produced, whereby it comprises all of the abovedescribed advantages.

Now referring to FIG. 9, the retrofitting method according to theinvention is described. In step i, the traction means tensioneraccording to the invention is provided. Separating the traction means ofthe welding device, especially a continuous chain or a continuous belt,so that the traction means comprises two ends takes place in step ii.The order of the two steps i and ii is arbitrary.

Now, and in step iii, the coupling of the first end of the tractionmeans to the first fastening portion of the first fastening means of thetraction means tensioner takes place, and in step iv, the coupling ofthe second end of the traction means to the second fastening portion ofthe second fastening means of the traction means tensioner is performed.Further, and in step v, the coupling means of the traction meanstensioner is arranged at the welding device, especially at an element ofthe welding device which is movable by means of the traction means. Theorder of the steps iii to v is also arbitrary. Preferably, theadjustment of the pretension of the traction means by means of adjustingthe distance between the first fastening portion of the first fasteningmeans and the second fastening portion of the second fastening meanstakes place as last step vi, especially by means of the regulatingportion of the coupling means. In this way, a common welding device isprovided with the traction means tensioner according to the inventionand thus comprises all of the above described advantages.

Further forms—the following numbered paragraphs and sentences furtherdescribe forms that may be carried out independently or in variouscombinations.

1. In at least some implementations, a traction means tensioner by meansof which a traction means is tensionable, which has at least a first anda second end, preferably only two ends, comprises:

a) a first fastening means (32) having a first fastening portion (42) atwhich the first end of the traction means (28) is fastenable,

b) a second fastening means (34) having a second fastening portion (64)at which the second end of the traction means (28) is fastenable, and

c) a coupling means coupling the first (32) and the second fasteningmeans (34) to each other so that the first (32) and the second fasteningmeans (34) are movable with respect to each other and their movabilityis at least restricted on one side, wherein

d) the first (32) and the second fastening means (34) arepre-tensionable with respect to each other via at least one springelement (38; 62).

2. Traction means tensioner (30) according to form 1, wherein the atleast one spring element (38; 62) is arranged adjacent to the secondfastening means 34 and the second fastening means (34) comprises asecuring portion (56) arranged in the coupling means.

3. Traction means tensioner (30) according to one or more of thepreceding forms, wherein the first fastening means (32) is stationarywith respect to the coupling means.

4. Traction means tensioner (30) according to one or more of thepreceding forms, wherein the coupling means couples the first (32) andthe second fastening means (34) to each other so that the firstfastening portion (42) of the first fastening means (32) and the secondfastening portion (64) of the second fastening means (34) are orientedin opposite axial directions.

5. Traction means tensioner (30) according to one or more of thepreceding forms, wherein the coupling means comprises a regulatingportion, especially a thread, so that a position of the first fasteningportion (42) with respect to the second fastening portion (64) isadjustable, especially a distance between the first (42) and the secondfastening portion (64).

6. Traction means tensioner (30) according to one or more of thepreceding forms, wherein the at least one spring element (38; 62) ischosen from the group consisting of: helical springs (38), spiralsprings, flat springs and disc springs (62) or a combination thereof.

7. Traction means tensioner (30) according to one or more of thepreceding forms, wherein the at least one spring element (38) is ahelical spring arranged with a first axial end at the second fasteningmeans (34), especially at the second fastening portion (64), and with asecond axial end at the coupling means so that the first (32) and thesecond fastening means (34) are pre-tensionable with respect to eachother.

8. Traction means tensioner (30) according to one or more of the forms 1to 6, wherein the at least one spring element (62) is a disc springarranged around the second fastening element (34) between a securingportion (56) of the second fastening element (34) and an opening in thecoupling means so that the first (32) and the second fastening means(34) are pre-tensionable with respect to each other.

9. Usage of a traction means tensioner (30) according to one or more ofthe forms 1 to 8 in a welding device, especially in a vibration weldingdevice 1, an infrared welding device, a hot plate welding device or incombinations thereof

10. Usage of a traction means tensioner (30) according to form 9,wherein the traction means tensioner (30) is used with a chain or a beltas traction means (28).

11. Welding device, especially a vibration welding device 1, comprising

a) a movably arranged element, especially a lifting table (14),

b) a traction means (28) for moving the movably arranged element,especially for a reciprocating movement of the lifting table (14), and

c) a traction means tensioner (30) according to one of the forms 1 to 8being coupled via a first fastening portion (42) to a first end of thetraction means (28) and via a second fastening portion (64) to thesecond end of the traction means (28).

12. Welding device according to form 11, wherein the traction meanstensioner (28) is arranged at the movably arranged element, especiallyat the lifting table (14), by means of the coupling means.

13. Production method of a traction means tensioner, especially of atraction means tensioner (30) according to one or more of the forms 1 to8, wherein the production method comprises the steps of:

a) providing (A) a first fastening means (32) having a first fasteningportion (42) at which a first end of a traction means (28) isfastenable,

b) providing (B) a second fastening means (34) having a second fasteningportion (64) at which a second end of a traction means (28) isfastenable,

c) providing (C) a coupling means and arranging (D) the first (32) andthe second fastening means (34) at the coupling means so that the first(32) and the second fastening means (34) are movable with respect toeach other and their movability is at least restricted on one side, and

d) arranging (E) at least one spring element (38; 62) so that the first(32) and the second fastening means (34) are pre-tensionable withrespect to each other via the at least one spring element (38; 62).

14. Retrofitting method for a welding device, comprising the steps of:

a) providing (i) a traction means tensioner (30) according to one ormore of the forms 1 to 8,

b) separating (ii) a traction means (28) of the welding device,especially a continuous chain or a continuous belt, so that the tractionmeans (28) has two ends,

c) coupling (iii) the first end of the traction means (28) to the firstfastening portion (42) of the first fastening means (32) of the tractionmeans tensioner (30),

d) coupling (iv) the second end of the traction means (28) to the secondfastening portion (64) of the second fastening means (34) of thetraction means tensioner (30), and

e) arranging (v) the coupling means of the traction means tensioner (30)at the welding device, especially at an element of the welding devicewhich is movable by means of the traction means.

15. Retrofitting method of a welding device according to form 14,comprising the further step of:

f) adjusting a pretension of the traction means (28) by means ofadjusting the distance between the first fastening portion (42) of thefirst fastening means (32) and the second fastening portion (64) of thesecond fastening means (34), especially by means of a regulating portionof the coupling means.

16. Tensioning method for a traction means (28) having at least a firstand a second end, comprising the following steps of:

a) connecting (a) the first and the second end of the traction means(28) via a coupling means so that the first and the second end of thetraction means (28) are movable with respect to each other and theirmovability is at least restricted on one side,

b) arranging (b) at least one spring element (38; 62) so that the firstand the second end of the traction means (28) are pre-tensionable withrespect to each other, and

c) changing (c) a relative distance between the first and the second endof the traction means (28), which are connected via the coupling meansso that the traction means (28) is pre-tensioned via a spring pretensionbetween the first and the second end.

17. Tensioning method according to form 16, wherein the step ofconnecting the first and the second end of the traction means (28) via acoupling means comprises the steps of:

d) coupling (d) the first end of the traction means (28) to a firstfastening means (32) coupled to the coupling means,

e) coupling (e) the second end of the traction means (28) to a secondfastening means (34) coupled to the coupling means, wherein

f) the first (32) and the second fastening means (34) are movable withrespect to each other and at least restricted on one side so that arelative distance between the first and the second end of the tractionmeans (28) is adjustable.

18. Tensioning method according to form 17, wherein the first (32)and/or the second fastening means (34) are coupled to the coupling meansso that a protection against a releasing of the first and/or the secondend of the traction means (28) from the coupling means is formed,especially in a traction direction of the traction means (28).

1. Production method of a traction mechanism tensioner, wherein theproduction method comprises the steps of: a) providing a first fastenerhaving a first fastening portion at which a first end of a tractionmechanism is fastenable, b) providing a second fastener having a secondfastening portion at which a second end of a traction mechanism isfastenable, c) providing a coupler and arranging the first and thesecond fasteners at the coupler so that the first and the secondfasteners are movable with respect to each other and their movability isat least restricted on one side, and d) arranging at least one springelement so that the first and the second fasteners are pre-tensionablewith respect to each other via the at least one spring element. 2.Retrofitting method for a welding device, comprising the steps of: a)providing a traction mechanism tensioner by which a traction mechanismis tensionable, which has at least a first and a second end, comprising,i) a first fastener having a first fastening portion at which the firstend of the traction mechanism is fastenable, ii) a second fastenerhaving a second fastening portion at which the second end of thetraction mechanism is fastenable, and iii) a coupler coupling the firstand the second fasteners to each other so that the first and the secondfasteners are movable with respect to each other and their movability isat least restricted on one side, wherein iv) the first and the secondfasteners are pre-tensionable with respect to each other via at leastone spring element, b) separating a traction mechanism of the weldingdevice, so that the traction mechanism has two ends, c) coupling thefirst end of the traction mechanism to the first fastening portion ofthe first fastener of the traction mechanism tensioner, d) coupling thesecond end of the traction mechanism to the second fastening portion ofthe second fastener of the traction mechanism tensioner, and e)arranging the coupler of the traction mechanism tensioner at the weldingdevice.
 3. Retrofitting method of a welding device according to claim 2,comprising the further step of: f) adjusting a pretension of thetraction mechanism by adjusting the distance between the first fasteningportion of the first fastener and the second fastening portion of thesecond fastener, by a regulating portion of the coupler.
 4. Tensioningmethod for a traction mechanism having at least a first and a secondend, comprising the following steps of: a) connecting the first and thesecond end of the traction mechanism via a coupler so that the first andthe second end of the traction mechanism are movable with respect toeach other and their movability is at least restricted on one side, b)arranging at least one spring element so that the first and the secondend of the traction mechanism are pre-tensionable with respect to eachother, and c) changing a relative distance between the first and thesecond end of the traction mechanism, which are connected via thecoupling means so that the traction mechanism is pre-tensioned via aspring pretension between the first and the second end.
 5. Tensioningmethod according to claim 4, wherein the step of connecting the firstand the second end of the traction mechanism via a coupling meanscomprises the steps of: d) coupling the first end of the tractionmechanism to a first fastener coupled to the coupling means, e) couplingthe second end of the traction mechanism to a second fastener coupled tothe coupling means, wherein f) the first and the second fasteners aremovable with respect to each other and at least restricted on one sideso that a relative distance between the first and the second end of thetraction mechanism is adjustable.
 6. Tensioning method according toclaim 5, wherein the first and/or the second fastener are coupled to thecoupling means so that a protection against a releasing of the firstand/or the second end of the traction mechanism from the coupling meansis formed, especially in a traction direction of the traction mechanism.7. Retrofitting method according to claim 2, wherein the at least onespring element is arranged adjacent to the second fastener and thesecond fastener comprises a securing portion arranged in the couplingmeans.
 8. Retrofitting method according to claim 2, wherein the firstfastener is stationary with respect to the coupling means. 9.Retrofitting method according to claim 2, wherein the coupling meanscouples the first and the second fasteners to each other so that thefirst fastening portion of the first fastener and the second fasteningportion of the second fastener are oriented in opposite axialdirections.
 10. Retrofitting method according to claim 2, wherein thecoupling means comprises a regulating portion, especially a thread, sothat a position of the first fastening portion with respect to thesecond fastening portion is adjustable, especially a distance betweenthe first and the second fastening portion.
 11. Retrofitting methodaccording to claim 2, wherein the at least one spring element is chosenfrom the group consisting of: helical springs, spiral springs, flatsprings and disc springs or a combination thereof.
 12. Retrofittingmethod according to claim 2, wherein the at least one spring element isa helical spring arranged with a first axial end at the second fastenerespecially at the second fastening portion, and with a second axial endat the coupling means so that the first and the second fasteners arepre-tensionable with respect to each other.
 13. Retrofitting methodaccording to claim 2, wherein the at least one spring element is a discspring arranged around the second fastening element between a securingportion of the second fastening element and an opening in the couplingmeans so that the first and the second fasteners are pre-tensionablewith respect to each other.